Monoglycerol difatty acid esters are found to have effects of lowering accumulation of body fat and thereby preventing obesity (Japanese Patent Application Laid-Open Nos. Hei 4-300826, Hei 10-176181), effects of lowering a blood cholesterol level by using in combination with a phytosterol (International Publication No. WO99/48378) or the like. It is known that a deep frying oil containing a monoglycerol difatty acid ester has an advantage of less foaming (Japanese Patent Application Laid-Open No. Hei 11-243857). It is also known that it can be applied to an emulsion (U.S. Pat. No. 5,879,735, Japanese Patent Application Laid-Open No. Hei 3-8431). In consideration of such advantages, a fat or oil composition having a high monoglycerol difatty acid ester content has been used widely as edible oil for domestic use.
A technique capable of suppressing sputtering upon stir-frying by adding, to this monoglycerol difatty acid ester, a specific phospholipid is known (Japanese Patent Application Laid-Open No. Hei 2-291228). Also disclosed are techniques of incorporating a polyglycerol fatty acid ester and sucrose fatty acid ester in a monoglycerol difatty acid ester to improve work efficiency and facilitate cooking and to improve texture (Japanese Patent Application Laid-Open No. Hei 7-16051), a fat or oil obtained by incorporating a polyglycerol fatty acid ester in a monoglycerol difatty acid ester and suited as a confectionery material (Japanese Patent Application Laid-Open No. Hei 6-220484), and a fat or oil improved in the solubility of a phytosterol (Japanese Patent Application Laid-Open No. 2001-220595).
On the other hand, techniques of improving workability to facilitate cooking such as stir-frying or deep frying by adding a polyglycerol fatty acid ester containing a medium chain fatty acid in a fat or oil are known (Japanese Patent Application Laid-Open Nos. Hei 9-52865, 2000-290682). The fat or oil obtained by this technique however emits an odor and taste typical of the medium-chain fatty acid upon heating.
As other known techniques relating to a diglycerol fatty acid ester, there have been techniques of utilizing a diglycerol di(saturated fatty acid) ester for flour products (Japanese Patent Application Laid-Open Nos. Hei 7-228550, 2002-112692).